Roof jacks, flashing plates or roof saddles have been used to provide a weather-tight cover over an opening through the roof of a building for stove pipes, vents, furnace pipes and air handlers. Typically, roof jacks include a portion attached to the roof and an upwardly extending portion, which is attached to a stove pipe vent, or the like. For air handlers, such as evaporative coolers, heat pumps, refrigeration units and the like, a portion of the roof jack is attached to the outlet duct of the air handler. Typically, roof jacks are made in a variety of angles for use with roofs having various standard pitches.
To reduce the inventory, which necessarily must be stocked for any particular type of roof jack, and, further, for permitting the use of roof jacks with non-standard roof pitches, adjustable roof jack assemblies or saddles have been designed. Six patents to Wallace U.S. Pat. No. 917,385; Dawson U.S. Pat. No. 1,192,279; McHale U.S. Pat. No. 1,332,224; Hoeft U.S. Pat. No. 1,703,670; Holtgreve U.S. Pat. No. 4,843,794; and Reaser U.S. Pat. No. 4,893,608, are directed to adjustable roof jacks for use with pipes extending up through the roof. In all of these patents, a base member which has a circular or spherical configuration is attached to the roof as the bottom portion of the jack. An upper cover member, having a complementary shape, is pivotally mounted on the base member; and the pipe or chimney extends through the upper member and is attached to it. The angle of pivot between the upper and lower members causes the devices to be usable on roofs of various pitches. In all cases, the lower or base member has a relatively wide slot in it compared to the opening in the top or upper member. The devices disclosed in all of these patents function in a comparable manner, with pivots located on opposite sides intermediate the upper and lower edges of the top member and attaching the top member to the lower member of the adjustable jack.
A different type of adjustable roof jack, more suitable for use with roof mounted air handlers such as evaporative coolers, air conditioners and heat pumps, is disclosed in the two patents to Sharp U.S. Pat. Nos. 4,526,091 and 4,781,401. The adjustable roof jack disclosed in both of these patents includes an upper member, which telescopes into a lower member, with the two members hinged together on the one end. The device of patent U.S. Pat. No. 4,526,091 is utilized as a roof jack between a roof mounted air handler and the roof, whereas the device of U.S. Pat. No. 4,781,401 is used to mount an air handler on top of an existing duct at a bend in the duct. The structure, however, disclosed in both of these patents for the adjustable jack is the same, with a bendable pivot or hinge being used on the front or uphill side of the device to pivot the two parts together.
A disadvantage with the roof jack assemblies utilizing circular or spherical parts is that the manufacture of parts in this shape is relatively complicated and expensive. The result is an assembly, which while it functions to provide the adjustability and weather resistant characteristics desired, cannot readily, inexpensively be made.
A significant disadvantage of the roof jack structures disclosed in the Sharp patent is that when the upper and lower units are hinged together at the front or upper side of the jack, only a relatively narrow range of adjustability for roofs of various pitches can be made from a single adjustable jack. Consequently, it has been necessary to provide an inventory of two or more jacks, each covering at least half of the range of pitches which can be encountered, in order to accommodate air handlers mounted on roofs of a wide range of varying pitches.
It is desirable to provide an adjustable roof jack which overcomes the disadvantages of the prior art listed above, which is readily manufactured from flat sheet stock material, and which is capable of a wide range of adjustment.